Human ZO1 Tight Junction Protein ELISA Kit (A313822) employs the sandwich enzyme immunoassay technique for the quantitative measurement of human ZO1 Tight Junction Protein in An antibody specific for ZO1 Tight Junction Protein has been pre-coated onto a 96-well microtiter plate. The standards and test samples are added into the wells and the ZO1 Tight Junction Protein present in each sample is bound to the wells by the immobilized antibody. Biotinylated Anti-ZO1 Tight Junction Protein Antibody, which also binds the ZO1 Tight Junction Protein present in each sample, and Streptavidin-HRP, which binds the Biotinylated Anti-ZO1 Tight Junction Protein Antibody, are added and the microtiter plate is incubated. Following incubation, unbound Biotinylated Anti-ZO1 Tight Junction Protein Antibody and unbound Streptavidin-HRP are removed by washing, and two substrate solutions are added to the wells. Color develops in proportion to the amount of ZO1 Tight Junction Protein captured in each well. The color development is stopped by addition of stop solution which changes the color from blue to yellow and the intensity of the color is then measured. The concentration of ZO1 Tight Junction Protein in the samples can then be calculated by reading the O.D. absorbance at 450nm in a microplate reader and referring to the standard curve.